gaffer
n.— «For his part, Chihuly called Rubino a “gaffer,” a term for a glassblower who labors around a furnace at the instruction of an artist. Asked to assess Rubino, Chihuly said, “He was an excellent craftsman” with little vision of his own.» —“Art: Ugly fight over glass creations” by Timothy Egan in Seattle, Washington International Herald Tribune (Paris, France) June 1, 2006. (source: Double-Tongued Dictionary)